Nowadays, new elevators typically include an emergency telephone. Furthermore, it is typically required that these emergency telephones are periodically tested. For example, European standards require that an elevator emergency telephone must make a test call at least every 3 days to a call receiver outside the building where the elevator is located. The test call ensures that the emergency telephone and its telecommunication means are in order.
The test call may be either a voice call or a data call, and the call must be such that the elevator the call is coming from can be identified. Since the calling elevator must be identified, the call must typically be answered. However, answering a call initiates phone costs for the caller, i.e. the elevator owner or the owner of the communication means of the elevator.
A customer care center of an elevator company may receive thousands of these test calls daily from both emergency telephones of its own manufacture as well as from third party emergency telephones. Receiving these check calls from various emergency telephone brands and versions requires many kinds of receivers with various telecommunication protocols, and plenty of telephone capacity and means to handle the capacity needed on the receiver side.
Today, a feature called Caller Line Identification (CLI) is in use in most countries. When the CLI is in place, the receiver of a call can identify from which telephone the call is coming from based on the CLI only—the call does not have to be answered at all and hence no costs are created for the caller. In other words, the CLI is a telephone service, available in analog and digital phone systems, that transmits a caller's telephone number to the called party's telephone equipment during the ringing signal, or when the call is being set up but before the call is answered.
However, the CLI is not widely utilized in test calls for elevator emergency telephones due to a number of problems. For example, the CLI is not always active by default, and activating it might incur costs for the elevator telephone means owner. Also, in many cases there are several elevator emergency phones sharing one phone line in a building, and hence a single elevator cannot be identified since the caller is one of the elevator emergency telephones on the same single line. Also, all elevator emergency telephones do not necessarily support a CLI based test call, e.g. an elevator emergency telephone might be configured to wait that a test call is answered and acknowledged in a certain way.
Accordingly, an object of the present invention is to alleviate the problems described above and to introduce a solution that allows utilizing the CLI feature in receiving test emergency calls from any kind of elevator emergency telephones.